The importance of observing patient vital signs in emergency department (ED) practice has been stressed in the literature. Failure of clinicians to respond to abnormal vital signs (AVS) has been described as a potential reason for delayed management in ED practice, with a likelihood of increased morbidity. This study aimed to explore and describe clinicians' responses to AVS in a busy ED. A qualitative descriptive approach was used with three focus groups being conducted with 18 volunteer registered nurses (RNs) and medical officers (MOs) who worked in the ED of an area health service in Western Sydney. Transcribed focus group interviews were analysed using a process of constant comparison and contrast and a description of clinicians' responses to AVS written. An analysis of text from focus groups revealed three main categories of clinicians' responses to AVS: identification, reporting and implementing action. Clinicians in this study recognised, reported and acted on AVS. However, delays in responding to AVS occurred due to a variety of reasons. The main reasons identified were issues with documentation and the ability to seek advice of appropriate staff, ineffective communication, fear of reprimand, inexperience of working in EDs, workload, distractions and interruptions. In conclusion, environmental and human factors contribute to inappropriate delays regarding AVS in the ED. These factors can be acted on by initiating appropriate education programmes and establishing improved communication networks. Better use of the existing medical emergency team (MET) in the ED can act to alleviate situations associated with delays in managing AVS.